1. Field of the Invention
The present invention relates to optical scanning systems for printers, and more particularly, to an optical scanning system for a printer that suppresses image print errors on a photosensitive belt due to variations in the amount of light repeatedly scanned by the photosensitive belt from an optical scanning unit.
2. Description of the Related Art
A printer may reproduce images or text on a photosensitive medium such as a photosensitive (or photoreceptor) belt to which toner is applied. Where a light beam strikes the photosensitive belt, it will hold developer for transfer to a sheet of paper.
An image is formed on the photosensitive belt by scanning the beam of light onto the photosensitive belt. Multiple rollers circulate the photosensitive belt, while a development unit develops the image to be printed on a transfer surface of the photosensitive belt. The developed image on the photosensitive belt is transferred to the paper or other printable medium when it passes the transfer unit.
For a high quality image to be printed, the positioning of the image on the photosensitive belt is important. One problem that occurs is that the image print starting position is irregularly set along the edge of the photosensitive belt in the traveling direction.
Exemplar of the background art U.S. Pat. No. 6,072,176 for Laser Beam Optical Scanning Device and Image Forming Apparatus with Laser Beam Optical Scanning Device issued to Kohsaka et al., U.S. Pat. No. 6,043,484 for Printer Optical Scanning Apparatus and Color Printer Optical Scanning System issued to Park, U.S. Pat. No. 5,138,479 for Light Beam Scanning Apparatus and Method of Detecting a Variation of a Scanning Speed of a Light Beam issued to Ando, U.S. Pat. No. 5,606,449 for Optical Scanning Device issued to Nishiyama, U.S. Pat. No. 5,365,364 for Optical Scanner and Printer issued to Taylor, U.S. Pat. No. 5,255,063 for Color Copying Apparatus with Improved Start Timing of a Scanner issued to Ideyama et al. disclose optical scanning systems for printers. I have found that the art does not show a way to reduce the irregularity of the starting position of the image print on a photosensitive medium of a printer.